<template>
  <div class="app-container">
    <h2 style="text-align: center">发布新课程</h2>
    <!-- 表格 -->
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px">
      <el-step title="填写课程基本信息" />
      <el-step title="创建课程大纲" />
      <el-step title="提交审核" />
    </el-steps>

    <!-- 进度条 -->
    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写" />
      </el-form-item>

      <el-form-item label="课程分类">
        <el-select
            v-model="courseInfo.subjectParentId"
            placeholder="一级分类" @change="subjectLevelOneChanged">
            <el-option
                v-for="subject in subjectRootList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
            <el-option
                v-for="subject in subjectSubList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>
      </el-form-item>

      <el-form-item label="课程讲师">
        <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">
            <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>

      <el-form-item label="课程封面">
        <el-upload
            :show-file-list="false"
            :on-success="handleAvatarSuccess"
            :before-upload="beforeAvatarUpload"
            :action="BASE_API + '/serviceoss/oss'"
            class="avatar-uploader">
            <img :src="courseInfo.cover" class="avatar">
        </el-upload>
      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrupdate">保存并下一步</el-button>
      </el-form-item>
    </el-form>
    
  </div>
</template>
<script>
import courseApi from "@/api/edu/course";
import teacherApi from "@/api/edu/teacher";
import subjectApi from "@/api/edu/subject";
import Tinymce from '@/components/Tinymce' //引入组件

const course_info_default = {
  title: '',
  subjectId: '',// 二级分类id
  subjectParentId: '',// 一级分类id
  teacherId: '',
  lessonNum: 0,
  description: '',
  cover: 'https://yuzhen169.oss-cn-shenzhen.aliyuncs.com/course/default/default.jpg',
  price: 0
};

export default {
  //声明组件
  components: { Tinymce },
  data () {
    return {
      BASE_API: process.env.BASE_API, // 接口API地址
      saveBtnDisabled: false,
      courseInfo: course_info_default,
      courseId: '',
      teacherList: [],
      subjectRootList: [],// 一级分类
      subjectSubList: [],// 二级分类
    };
  },

  created () { 
    // 获取路由id值
    if(this.$route.params && this.$route.params.id) {
      this.courseId = this.$route.params.id;
      // 调用根据id查询课程的方法
      this.getCourseInfo();
      return;
    } 
    this.courseInfo = course_info_default;
    // 初始化所有讲师
    this.getListTeacher();
    // 初始化一级分类
    this.getRootSubject();
  },

  methods: {
    getCourseInfo(){
      courseApi.getCourseInfoById(this.courseId).then(response => {
        this.courseInfo = response.data.courseInfo;
        // 初始化所有讲师
        this.getListTeacher();
        // 初始化一级分类
        this.getRootSubject();
      })
    },
    saveOrupdate () {
      // 判断添加还是修改
      if (!this.courseInfo.id) {
         this.saveData();
         return;
      }
      this.udpateData();
    },
    saveData () {
      courseApi.addCourseInfo(this.courseInfo).then(response => {
        this.$message({
          type: 'success',
          message: response.message
        })
        return response;
      }).then(response => {
        this.$router.push({ path: '/edu/course/chapter/' + response.data.courseId })
      })
    },
    udpateData () {
      courseApi.updateCourseInfo(this.courseInfo).then(response => {
        this.$message({
          type: 'success',
          message: response.message
        })
        this.$router.push({ path: '/edu/course/chapter/' + this.courseId })
      })
    },
    getListTeacher(){
      teacherApi.allTeacher().then(response => {
        this.teacherList = response.data.list;
      })
    },
    getRootSubject(){
      subjectApi.getSubjectTreeList().then(response => {
        this.subjectRootList = response.data.list;
        // 二级分类id有值，就自动的去选中
        if(this.courseInfo.subjectId){
          this.subjectLevelOneChanged(this.courseInfo.subjectParentId, this.courseInfo.subjectId);
        }
      })
    },
    subjectLevelOneChanged(rootId, subjectIdVal){
      this.subjectRootList.forEach(subjectRoot => {
        if(subjectRoot.id == rootId){
          this.subjectSubList = subjectRoot.children;
          this.courseInfo.subjectId = subjectIdVal;
          return;
        }
      });
    },
    // 上传封面成功调用的方法
    handleAvatarSuccess(res, file) {
        this.courseInfo.cover = res.data.url
    },
    // 上传之前调用的方法
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg';
      const isLt2M = file.size / 1024 / 1024 < 2;
      if (!isJPG) {
          this.$message.error('上传头像图片只能是 JPG 格式!');
      }
      if (!isLt2M) {
          this.$message.error('上传头像图片大小不能超过 2MB!');
      }
      return isJPG && isLt2M;
    },
  },
};
</script>
<style scoped>
.avatar {
  width: 178px;
  height: 178px;
  display: block;
}
.tinymce-container {
  line-height: 29px;
}
</style>